1. Field of the Invention:
The present invention relates to novel aluminum phosphates, to a process for the preparation thereof, and to binder/hardener compositions and ceramic materials comprising same.
2. Description of the Prior Art
Inorganic binders based on aluminum phosphates have long been known to this art. Typically, a refractory compound such as Al.sub.2 O.sub.3 or SiO.sub.2 is formulated with a binder which essentially consists of an aluminum or chromium hydrogenphosphate or phosphoric acid.
Another type of binder is prepared by admixing aluminum and phosphoric acid in an Al/P molar ratio of approximately 1, at about 100.degree. C. A very viscous suspension is thus obtained which is difficult to dry and, for this reason, is difficult to use.
Moreover, "chemically bonded" ceramic components are desiderata in this art, namely, those produced at moderate temperatures, for example, below 400.degree. C., from a mixture of aluminum and phosphoric acid. These mixtures are formulated in the form of a paste, the use of which, especially at the compacting step, is awkward.
Therefore, need continues to exist for starting materials which are easier to use for the preparation of binders or of ceramic components based thereon, such components, of course, necessarily having to display sufficient mechanical properties.